Knife changing board



Jan. 16, 1962 B. E. PRE\IIOST EIAL 3,017,177

KNIFE CHANGING BOARD Filed June 12, 1958 @m 0 T .T S T my: P1P MM 3% r v United States Patent O 3,017,177 KNIFE CHANGING BOARD Bruno E. Prevost, West Boxford, Mass., and Paul N. St. Onge, Madewaslra, Maine, assignors to John W. Bolton & Sons, Inc., Lawrence, Mass., a corporation of Massachusetts Filed June 12, 1958, Ser. No. 741,672 Claims. (Cl. 269-205) This invention relates to a machine knife changing device for use in paper cutting machines.

In paper cutting machines an elongated, heavy, sharp, cutting knife is usually detachably mounted on the knife bar by bolts and the knife and bar reciprocate vertically to trim stacks of paper on the platform of the machine. When the cutting edge of the machine knife requires sharpening, it is an awkward task for the operator to remove and replace the knife without cutting or straining himself and without dropping the knife on its edge.

The object of this invention is to provide mechanical leverage mechanism which enables an operator to maneuver a knife into and out of position with one hand while the other hand is free to turn the attaching bolts.

A further object of the invention is to provide a knife changer in which a knife cradle is oscillatably mounted on a leverage board thereby permitting the knife to be turned on a vertical axis, through a predetermined angular distance only, to engage on the attaching means of a knife bar.

Another object of the invention is to provide a knife changer with an oscillatably mounted, slotted cradle for holding the knife, the slot being of such configuration as to receive the cutting edge portion without engaging the cutting edge itself, while permitting the knife to tilt slightly in the slot.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawings and from the drawings in which FIG. 1 is a side view of the knife changer of the invention, in section On line 1--1 of FIGURE 2.

FIG. 2 is a front view thereof.

FIG. 3 is a plan view thereof.

FIG. 4 is a side view in section on line 4-4 of FIG. 3 and FIG. 5 is an enlarged side view, in section, showing the configuration of the knife slot.

As shown in FIGS. 1 and 2 the paper cutting machine includes a bed or platform 20 on which the paper to be cut is supported and a suitable frame, not shown, for guiding and supporting a reciprocating knife bar 21. The

bar 21 is formed with suitable threaded bolt holes 22 for.

the attaching bolts 23 which detachably support the machine knife 24. The machine knife 24 includes the body portion 25, a beveled cutting face 26, a face 27 and a cutting edge 28. Suitable holes 29 in body 25 receive the bolts 23.. A cutting machine such as described above is well known and it is illustrated fragmentarily to show the relation of the knife changer 31 of this invention therewith.

The knife changer 31 comprises lever means 32 of rigid material having a laterally extending handle 33 at one end and a relatively broad fulcrum engaging edge 34 at the opposite, free, terminal end. The fulcrum engaging edge 34 is of substantial width for example about eight inches and the lever means 32 is about four feet in length so that the device can support a machine knife of five or more feet in length centrally thereof, without danger of twisting on its longitudinal axis. Preferably the lever means 32 is a wood board of substantial uniform width and the handle 33 is formed by the aperture 35, located proximate the end of the board. The use of 3,017,177 Patented Jan. 16, 1962 wood for the lever means 32 prevents scratching of the surface of the platform 20 and also permits the device to be made at low cost.

Knife changer 31 is provided with cradle means 37 preferably in the form of a flat disc 38 mounted to swing in a horizontal plane on a vertical axis on the lever means 32 by means of the pivot pin '39. The disc 38 is preferably of wood or fibreboard and the underface 40 thereof is supported over substantially all of its area by the wide board forming the lever means 32. Cradle means 37 also includes an upstanding block 41 which extends dia metrically across the disc 38 and is fixed thereto by suitable means such as the screws 42. Block 41 is also preferably of wood and includes a knife receiving slot 44 which extends diametrically across the top face 45 of the block and disc from one end to the other.

As best shown in FIG. 5 the knife slot 44 in the cradle means 37 is formed by a vertical wall 46, on the side of the slot towards the fulcrum engaging means 34 and an inclined wall 47, opposite to, and spaced from wall 46 thereby forming a slot mouth 48 which terminates in a constricted throat 49. Below throat 49 the walls 46 and 47 are undercut as at 51 and 52 to form an enlarged pocket 53 for receiving but not touching the cutting edge 28 of knife 24, when the cutting faces 26 and 27 are engaged in the throat 49. The configuration of slot 44 is such that a machine knife may pivot therein from the position shown in dotted lines in FIG. 5, while it is supported by the bolts 23 to the position shown in full lines in FIG. 5 when it has tilted away from the bolts 23 and bar 21 and is supported in the knife changer 31 only.

Limit means 55 is provided on knife changer 31 to control oscillation of the cradle means 37 to a predetermined arc of about five degrees of angular displace ment around the axis formed by pin 39. Preferably an arcuate slot 56 is formed in disc 38 and an upstanding pin 57 which fits the slot is mounted on the lever means 32 for the purpose. The cradle means 37 may thus oscillate only one or two degrees angularly on each opposite side of the longitudinal centre line of the lever means 32.

In operation the knife changer 31 is placed as shown in FIG. 1 with the fulcrum engaging edge 34 supported on the platform 20 as a fulcrum, the slot 44 supporting the machine knife 24 and the operator's left hand on the handle 33 to support the device. The operators right hand is then free to unfasten the bolts 23 whereupon the knife 24 may be tilted away from any fixed studs or other support means of the bar 21, into the position shown in dotted lines in FIG. 5 without danger of the knife falling out of the slot. The knife 24 may then be lowered and slid along platform 20 until it is easily grasped for sharpening or the like. Upon reinstallation, the procedure is reversed with the operator able to lift the knife 24 with one hand while swinging the knife on the pin 39 until the holes in the knife register with the fastening means on the bar 21. While still holding the knife in position with one hand the operator can then attach and tighten the bolts 23 to complete the attachment of the knife.

Preferably a pair of pads of rubber 60 and 61 are detachably mounted, by key slots such as 62 on headed elements such as 63, on lever means 32 and may be placed on platform 20 under each opposite end of knife 24 to cushion the cutting edge 28 during the use of knife changer 31. The knife changer 31, permits one man installation of machine knives with safety to the operator and to the cutting edge and 'alignability of the machine knife as it is raised or lowered speeds the installation to a considerable degree.

We claim:

1. A machine knife changer comprising a longitudinally extending lever of rigid material having a laterally extending handle at one free terminal end and a laterally extending, relatively broad, fulcrum engaging edge at the opposite free terminal end for preventing rotation of said lever around its longitudinal axis; a machine knife cradle pivot'ally mounted on said lever, intermediate of the length thereof, to swing in a plane parallel to the plane of said lever, said cradle having laterally extending, upstanding walls defining a knife receiving slot in the upper face thereof for receiving and supporting the cutting edge portion of a knife and limit means, mounted on said knife changer, limiting the swing of said cradle relative to said lever to a predetermined angular distance.

2. A combination as specified in claim 1 wherein said cradle comprises a fiat disc with an upstanding block secured diametrically thereacross and the intermediate portion of said lever is substantially equal in width to the diameter of said disc for underlying and supporting the same.

3. A combination as specified in claim 1 wherein said limit means comprises an arcuate slot in said cradle and an upstanding pin in said lever, said pin fitting in said slot and limiting the rotation of said cradle to the are formed by said slot.

4. A combination as specified in claim 1 wherein the knife slot in said cradle is formed by a vertical wall and an opposite, inclined Wall at a spaced distance therefrom, said Walls forming a slot mouth terminating in a constricted throat and undercut Walls below said throat ldefining an enlarged pocket for receiving the cutting tip of a knife when the cutting faces thereof are engaged by said throat.

5. A machine knife changer comprising a wood lever of uniform width having a laterally extending handle at one free terminal end and a laterally extending, fulcrum engaging, edge at the opposite, free terminal end thereof; a flat wood disc pivotally mounted, intermediate of the length of said lever, for oscillation in a plane parallel to the plane of said lever, said disc having an arcuate slot therein; a wood block secured diametrically across the outer face of said disc, said block having a straight, knife-receivingslot extending laterally across the upper face thereof. with a constricted throat and an enlarged References Cited in the file of this patent UNITED STATES PATENTS 1,665,979 Rawlings -n Apr. 10, 1928 1,743,946 Williams Ian. 14, 1930 2,040,719 Walch May 12, 1936 2,396,161 Cullen Mar. 5,, 1946 2,660,833 Weber Dec. 1, 1953 

